Active Electronically Steered Array Research Articles

Investigations on Monolithic Radome Interactions with Active Electronically Scanned Array on Fighter Platform

The conventional fighter aircrafts are often equipped with fire control radar (FCR) using mechanically scanned antenna (MSA) with passive slots enclosed with monolithic conical radome. When the fighter platforms get upgraded with the modern active electronically steered array (AESA) FCR for better mission capabilities, even though radome change is desirable for optimum performance of AESA, it may not be feasible due to development time. This necessitate the evaluation of AESA radar with the existing monolithic radome. Hence active antenna aperture radiation pattern is required to be assessed with monolithic radome. To address this issue, simulation is preferred over physical testing, due to the reduced cost, time and complexity in measurements and ability to verify compatibility. In the present paper, the influence of monolithic radome on the active antenna radiation patterns are simulated and analysed. The characterisation studies helped for better optimisation of active aperture, optimum size for new radome development and additional space on fighter platforms that can be used for integration of new subsystems. Simulations are performed at two different locations of antenna inside radome. Experimental validations have been carried out to prove the efficacy of simulated results, which are in agreement.

Active Electronically Steered Array (AESA) Radar Data Visualization Software

Active Electronically Steered Array (AESA) Radar Data Visualization Software

Compensation Method for a Wideband Signal’s Squint Problem of an AESA SAR System Using a Cross-Range-Variant Antenna Gain Equalizer

In order to obtain a high-resolution image, a wideband signal is required in a synthetic aperture radar (SAR). However, in an active electronically steered array (AESA) SAR, consideration of the beam squint problem is indispensable especially when a forward directed AESA operates in a squint spotlight SAR mode. In this paper, we present an accurate compensation method for the squint problem without added hardware, such as true time delays. To clarify the beam squint effect, an antenna gain radiated to point targets located on the ground was derived and we confirmed that the antenna gain for the targets placed on the same cross-range axis has similar tendency within 1.5-dB difference. Based on the results, we proposed a cross-range-variant antenna gain equalizer. Through test simulations, we confirmed that the suggested method effectively compensated for the degraded resolution performance of about 14% for the AESA SAR.

An Airborne Radar Sensor for Maritime and Ground Surveillance and Reconnaissance—Algorithmic Issues and Exemplary Results

The pod integrated variant of the airborne SmartRadar by AIRBUS Defence and Space, mounted under the wing of a Learjet 35 aircraft, is used as a testbed to develop advanced radar modes. In particular, it offers the capabilities of a multiphase-center active electronically steered array (AESA) antenna and of a flexible, wide-bandwidth radar core. During the last 2 years, the already-operated synthetic aperture radar (SAR) and ground moving target indication (GMTI) modes have been supplemented by newly developed maritime modes. This overview paper discusses the new maritime modes, presents recent results from our 2013/14 flight campaigns, and points out some interesting technological aspects with focus on algorithmic issues. In particular, maritime modes for open-sea surveillance, maritime MTI, and inverse SAR imaging of ships are discussed in detail. All of these radar modes make use of the instantaneous repointing capability of the fixed-mounted AESA antenna.

실시간으로 적응빔형성 및 신호처리를 수행하는 평면능동위상배열 레이더 시스템 개발

Interference and jamming are becoming increasing concern to a radar system nowdays. AESA(Active Electronically Steered Array) antennas and adaptive beamforming(ABF), in which antenna beam patterns can be modified to reject the interference, offer a potential solution to overcome the problems encountered. In this paper, we`ve developed a planar active phased array radar system, in which ABF, target detection and tracking algorithm operate in real-time. For the high output power and the low noise figure of the antenna, we`ve designed the S-band TRMs based on GaN HEMT. For real-time processing, we`ve used wavelenth division multiplexing technique on fiber optic communication which enables rapid data communication between the antenna and the signal processor. Also, we`ve implemented the HW and SW architecture of Real-time Signal Processor(RSP) for adaptive beamforming that uses SMI(Sample Matrix Inversion) technique based on MVDR(Minimum Variance Distortionless Response). The performance of this radar system has been verified by near-field and far-field tests.